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common.py

# -*-python-*-
#
# Copyright (C) 1999-2006 The ViewCVS Group. All Rights Reserved.
#
# By using this file, you agree to the terms and conditions set forth in
# the LICENSE.html file which can be found at the top level of the ViewVC
# distribution or at http://viewvc.org/license-1.html.
#
# For more information, visit http://viewvc.org/
#
# -----------------------------------------------------------------------

"""common.py: common classes and functions for the RCS parsing tools."""

import time
import string

### compat isn't in vclib right now. need to work up a solution
import compat


class Sink:
  def set_head_revision(self, revision):
    pass
  def set_principal_branch(self, branch_name):
    pass
  def define_tag(self, name, revision):
    pass
  def set_access(self, accessors):
    pass
  def set_expansion(self, mode):
    pass
  def set_locking(self, mode):
    """Used to signal locking mode.

    Called with mode argument 'strict' if strict locking
    Not called when no locking used."""
    pass
  def set_locker(self, revision, locker):
    pass
  def set_comment(self, comment):
    pass
  def set_description(self, description):
    pass
  def define_revision(self, revision, timestamp, author, state,
                      branches, next):
    pass
  def set_revision_info(self, revision, log, text):
    pass
  def admin_completed(self):
    pass
  def tree_completed(self):
    pass
  def parse_completed(self):
    pass


# --------------------------------------------------------------------------
#
# EXCEPTIONS USED BY RCSPARSE
#

class RCSParseError(Exception):
  pass
class RCSIllegalCharacter(RCSParseError):
  pass
### need more work on this one
class RCSExpected(RCSParseError):
  def __init__(self, got, wanted):
    RCSParseError.__init__(self, got, wanted)

class RCSStopParser(Exception):
  pass

# --------------------------------------------------------------------------
#
# STANDARD TOKEN STREAM-BASED PARSER
#

class _Parser:
  stream_class = None   # subclasses need to define this

  def parse_rcs_admin(self):
    while 1:
      # Read initial token at beginning of line
      token = self.ts.get()

      # We're done once we reach the description of the RCS tree
      if token[0] in string.digits:
        self.ts.unget(token)
        return

      if token == "head":
        semi, rev = self.ts.mget(2)
        self.sink.set_head_revision(rev)
        if semi != ';':
          raise RCSExpected(semi, ';')
      elif token == "branch":
        semi, branch = self.ts.mget(2)
        if semi == ';':
          self.sink.set_principal_branch(branch)
        else:
          if branch == ';':
            self.ts.unget(semi);
          else:
            raise RCSExpected(semi, ';')
      elif token == "symbols":
        while 1:
          tag = self.ts.get()
          if tag == ';':
            break
          self.ts.match(':')
          tag_name = tag
          tag_rev = self.ts.get()
          self.sink.define_tag(tag_name, tag_rev)
      elif token == "comment":
        semi, comment = self.ts.mget(2)
        self.sink.set_comment(comment)
        if semi != ';':
          raise RCSExpected(semi, ';')
      elif token == "expand":
        semi, expand_mode = self.ts.mget(2)
        self.sink.set_expansion(expand_mode)
        if semi != ';':
          raise RCSExpected(semi, ';')
      elif token == "locks":
        while 1:
          tag = self.ts.get()
          if tag == ';':
            break
          (locker, rev) = string.split(tag,':')
          self.sink.set_locker(rev, locker)

        tag = self.ts.get()
        if tag == "strict":
          self.sink.set_locking("strict")
          self.ts.match(';')
        else:
          self.ts.unget(tag)
      elif token == "access":
        accessors = []
        while 1:
          tag = self.ts.get()
          if tag == ';':
            if accessors != []:
              self.sink.set_access(accessors)
            break
          accessors = accessors + [ tag ]

      # Chew up "newphrase"
      else:
        pass
        # warn("Unexpected RCS token: $token\n")

    raise RuntimeError, "Unexpected EOF"

  def parse_rcs_tree(self):
    while 1:
      revision = self.ts.get()

      # End of RCS tree description ?
      if revision == 'desc':
        self.ts.unget(revision)
        return

      # Parse date
      semi, date, sym = self.ts.mget(3)
      if sym != 'date':
        raise RCSExpected(sym, 'date')
      if semi != ';':
        raise RCSExpected(semi, ';')

      # Convert date into timestamp
      date_fields = string.split(date, '.') + ['0', '0', '0']
      date_fields = map(string.atoi, date_fields)
      # need to make the date four digits for timegm
      EPOCH = 1970
      if date_fields[0] < EPOCH:
          if date_fields[0] < 70:
              date_fields[0] = date_fields[0] + 2000
          else:
              date_fields[0] = date_fields[0] + 1900
          if date_fields[0] < EPOCH:
              raise ValueError, 'invalid year'

      timestamp = compat.timegm(tuple(date_fields))

      # Parse author
      ### NOTE: authors containing whitespace are violations of the
      ### RCS specification.  We are making an allowance here because
      ### CVSNT is known to produce these sorts of authors.
      self.ts.match('author')
      author = ''
      while 1:
        token = self.ts.get()
        if token == ';':
          break
        author = author + token + ' '
      author = author[:-1]    # toss the trailing space

      # Parse state
      self.ts.match('state')
      state = ''
      while 1:
        token = self.ts.get()
        if token == ';':
          break
        state = state + token + ' '
      state = state[:-1]      # toss the trailing space

      # Parse branches
      self.ts.match('branches')
      branches = [ ]
      while 1:
        token = self.ts.get()
        if token == ';':
          break
        branches.append(token)

      # Parse revision of next delta in chain
      next, sym = self.ts.mget(2)
      if sym != 'next':
        raise RCSExpected(sym, 'next')
      if next == ';':
        next = None
      else:
        self.ts.match(';')

      # there are some files with extra tags in them. for example:
      #    owner  640;
      #    group  15;
      #    permissions  644;
      #    hardlinks    @configure.in@;
      # this is "newphrase" in RCSFILE(5). we just want to skip over these.
      while 1:
        token = self.ts.get()
        if token == 'desc' or token[0] in string.digits:
          self.ts.unget(token)
          break
        # consume everything up to the semicolon
        while self.ts.get() != ';':
          pass

      self.sink.define_revision(revision, timestamp, author, state, branches,
                                next)

  def parse_rcs_description(self):
    self.ts.match('desc')
    self.sink.set_description(self.ts.get())

  def parse_rcs_deltatext(self):
    while 1:
      revision = self.ts.get()
      if revision is None:
        # EOF
        break
      text, sym2, log, sym1 = self.ts.mget(4)
      if sym1 != 'log':
        print `text[:100], sym2[:100], log[:100], sym1[:100]`
        raise RCSExpected(sym1, 'log')
      if sym2 != 'text':
        raise RCSExpected(sym2, 'text')
      ### need to add code to chew up "newphrase"
      self.sink.set_revision_info(revision, log, text)

  def parse(self, file, sink):
    self.ts = self.stream_class(file)
    self.sink = sink

    self.parse_rcs_admin()

    # let sink know when the admin section has been completed
    self.sink.admin_completed()

    self.parse_rcs_tree()

    # many sinks want to know when the tree has been completed so they can
    # do some work to prep for the arrival of the deltatext
    self.sink.tree_completed()

    self.parse_rcs_description()
    self.parse_rcs_deltatext()

    # easiest for us to tell the sink it is done, rather than worry about
    # higher level software doing it.
    self.sink.parse_completed()

    self.ts = self.sink = None

# --------------------------------------------------------------------------

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